1. Solubility

2. Today’s class: Solubility Saturation Separation of mixtures

3. precipitate unsaturated solution saturated solution remaining undissolved solute

4. Practice solubility / saturated solution Solubility:Maximum concentration of a solute that can be attained in given solvent. Saturated Solution: Contains maximum amount of solute that can be dissolved. Unsaturated Solution: More solute can be dissolved in the solution. Supersaturated Solution: An extra amount of solute was dissolved; solution “wants” to precipitate some solute Maximum amount of solute that can be dissolved in a given amount of solvent.

5. 2.65 g of a solute is dissolved in 70.0 mL of water to produce a saturated solution at 20 o C. Calculate the solubility in units of g/100 mL; g/L. m = 2.65 g v = 70 ml 1.) in g/100ml = % m/v 100 mL = m solute v solution g/100ml = ? 100 mL = 2.65 g 70 ml 100 mL= 2.65 g 70 ml = 3.79 g The solubility is 3.79 g /100 mL

6. 2.65 g of a solute is dissolved in 70.0 mL of water to produce a saturated solution at 20 o C. Calculate the solubility in units of g/100 mL; g/L. 2.) in g/L c = m solute v solution m = 2.65 g v = 70 mL c = ? g/L = 0.07 L = 2.65 g 0.07 L c = 37.9 g/L The solubility is 37.9 g /L

7. Example 2 4.5 g is the maximum amount of a solute that can be dissolved in 200 mL of water at 20 o C. Calculate the solubility in units of g/100 mL; g/L.

8. Effect of temperature on solubility How to make a supersaturated solution 1.) make a saturated solution at high temperature 2.) let hot, saturated solution cool  supersaturated 3.) eventually excess solute will PRECIPATE (form new crystals)

9.  For most solids solubility increases with temperature Temperature °C solubility (g/100 ml of water)

10. Solubility of gases and temperature Air bubbles forming, before the water starts to boil

11. Solubility of most gases decreases with temperature  When oceans warm up, less CO 2 can be dissolved – CO 2 is released

12. Solubility and solvent salt ? Solubility of a substance depends on the nature of the solvent salt is soluble in water salt is not soluble in oil

13. Substances that are soluble in water are called hydrophilic Substances that are soluble in oil are called lipophilic Soap has a hydrophilic and a lipophilic part and can help oily substances dissolve in water.

15. Solubility Saturation Separation of mixtures

16. Separating mixtures Most substances are not found in their pure form in nature but need to be isolated from a mixture.

17. Separating solid and liquid - a difference in state of matter Filtration

18. A difference in density I Decantation water oil Example: Pouring water off rice / pasta (without using a strainer).

19. A difference in density II Centrifugation Example: Centrifugation of blood samples Accelerates and improves sorting by density  dense material collects at the bottom

20. A difference in speed of travel Chromatography Mixture is separated into its components using paper and a solvent. The different components of the mixture are transported by the solvent along the paper, but with different speeds.

21. Isolating a solute - evaporation The liquid solvent is evaporated, leaving behind the solid solvent Example: Harvesting of sea salt form the ocean.

22. A difference in boiling point Distillation Example: Distilling wine to make brandy.

23. Notes on separating mixtures

24. Homework Solubility: work book p. 8 # 4, 5 p. 10 # 9 Separating mixtures p. 12